What is the characteristic shape of koilonychia?

Koilonychia, often referred to as spoon nails, is characterized by a concave shape. In this condition, the nails curve inward, resembling the shape of a spoon. This abnormal nail shape can indicate underlying health issues, such as iron deficiency anemia or other systemic conditions. Recognizing koilonychia is important because it can be a sign of nutritional deficiencies or medical conditions that may require further investigation. The concave structure is distinct and helps differentiate it from other nail shapes, enabling both cosmetologists and healthcare professionals to identify potential health problems in clients.